Sawyer’s, a local bakery, is worried about increased costs—particularly energy. Last year’s records can provide a fairly good estimate of the parameters for this year. Judy Sawyer, the owner, does not believe things have changed much, but she did invest an additional $3,000 for modifications to the bakery’s ovens to make then more energy efficient. The modifications were supposed to make the ovens at least 15% more efficient. Sawyer has asked you to check the energy savings of the new ovens and also to look over other measures of the bakery’s productivity to see if the modifications were beneficial.
You have the following data to work with: